In-tank fuel pump modules are used in automotive fuel delivery systems to draw fuel from a fuel tank and supply the fuel under pressure for delivery to an engine. These modules usually include a mounting flange closing an opening in an upper wall of the tank, a fuel reservoir carried by the mounting flange and disposed within the fuel tank, a fuel pump assembly disposed in the reservoir, and several hoses and hose interconnections between and among the mounting flange, fuel reservoir, and fuel pump assembly.
In conventional electric motor driven fuel pump assemblies, a pump discharges fuel through a motor housing to cool the motor as the fuel flows past the motor and out of the pump outlet. Such assemblies experience a high viscous drag because the armature is spinning in a liquid such as gasoline or diesel fuel rather than air. As the viscous drag increases, more motor torque is required to overcome that drag. Thus, more power is required to spin the armature in a liquid than in a gas. This is frequently referred to as windage losses. Such windage losses limit the efficiency of such assemblies.
Moreover, automobile designers find it increasingly desirable to package fuel tanks in vertically confined spaces such as underneath a rear seat of a vehicle. But, current fuel pump modules are axially too tall to be packaged in such a location. Accordingly, in-tank fuel pump modules are typically modified to accommodate various requirements peculiar to different vehicle applications. But this approach generally requires extensive retooling to provide a compatible design for each separate vehicle application.